A Farewell to the Arecibo Observatory

On December 1, 2020, Arecibo's long history came came to an end when it crashed and collapsed. It collapsed some time after it was scheduled to be dismantled.  This monumental observatory served a lot of years. It has made many fantastic discoveries over the last 60 years.

After suffering damage in recent months, the Arecibo Observatory radio telescope in Puerto Rico really collapsed on December 1. Cables that suspended a platform of scientific instruments above the dish snapped, causing the platform to fall into the dish.

The Arecibo Observatory is also known as the National Astronomy and Ionosphere Center (NAIC). This is an observatory in Arecibo, Puerto Rico owned by the US National Science Foundation (NSF).

The observatory's main instrument was the Arecibo Telescope, a 305 m (1,000 ft) spherical reflector dish built into a natural sinkhole, with a cable-mount steerable receiver and several radar transmitters for emitting signals mounted 150 m (492 ft) above the dish. Completed in 1963, it was the world's largest single-aperture telescope for 53 years, impressively surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China.

After the 2 cable breaks supporting the receiver platform in the prior months, the NSF stated on November 19, 2020 that it was decommissioning the telescope due to safety concerns. On December 1, 2020 the main telescope collapsed before any controlled demolition could be conducted.

The impressive space observatory also includes a radio telescope, a LIDAR facility, and a visitor center, all which are expected to remain operational after the damage from the main telescope collapse is assessed.

LIDAR (sometimes also written as "LiDAR", "Lidar", or "LADAR") is used in a wide range of various land management and planning efforts, including hazard assessment (including lava flows, landslides, tsunamis, and floods), forestry, agriculture, geologic mapping, and watershed and river surveys.

Lidar is a method for measuring distances by illuminating the target with laser light and measuring the reflection with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3-D representations of the target. It has terrestrial, airborne, and mobile applications.

You might have thought about what is the biggest observatory in the world: Gran Telescopio Canarias. Located 2,267 metres (7,438ft) above sea level in La Palma, Canary Islands, the Gran Telescopio Canarias is currently the world's impressive largest single aperture telescope.

In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.